Backlighting appliance deadfronted user interfaces

ABSTRACT

A capacitive touch switch is disclosed which includes a transparent insulating panel, a filtering layer having an opaque color, a transparent icon being defined in the filtering layer, a transparent substrate including a capacitive electrode, the transparent substrate being tinted to substantially match the opaque color of the filtering layer, and a light source configured to transmit light through the transparent substrate, the transparent icon, and the transparent insulating panel when energized. A user interface and a method of manufacturing a capacitive touch switch are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is a continuation of and claims priority to U.S. patentapplication Ser. No. 15/871,799, entitled “BACKLIGHTING APPLIANCEDEADFRONTED USER INTERFACES,” filed on Jan. 15, 2018, which is acontinuation of U.S. patent application Ser. No. 15/457,303 (now U.S.Pat. No. 9,871,515), entitled “BACKLIGHTING APPLIANCE DEADFRONTED USERINTERFACES,” filed on Mar. 13, 2017, which is a continuation of U.S.patent application Ser. No. 12/773,054 (now U.S. Pat. No. 9,595,960),entitled “DEAD-FRONT USER INTERFACE,” filed on May 4, 2010, the entiredisclosures of which are hereby incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to capacitive touch switcheswhich may be utilized in the user controls of domestic appliances or anyother devices which employ low-profile user controls. More particularly,the present disclosure relates to a capacitive touch switch capable ofdisplaying a dead-front user interface.

BACKGROUND

Capacitive touch switches may be incorporated into the user controls ofdevices such as domestic appliances (for example, ovens, microwaves,dishwashers, etcetera) to replace traditional buttons and to provide alow-profile user interface. In the present disclosure, the term“capacitive touch switch,” or “switch,” refers to any type of sensorwhich detects the proximity or position of a user (typically, a user'sfinger) via a change in the capacitance of one or more electrodes.Several capacitive touch switches may be arranged along a panel, alongwith associated control circuitry, to form a user interface. Each switchmay be associated with an icon disposed on the panel.

Visual feedback regarding the status or activation of a particularcapacitive touch switch may be provided to a user by selectivelyilluminating the icon associated with the switch. By way of example, anicon may be semi-transparent, and a light source associated with theicon may cause light to shine through portions of the icon. When an iconis not illuminated, it may be desirable for the icon to be invisible orsubstantially invisible to the user. When some or all of the icons in auser interface disappear from view, a dead-front effect results in whichthe panel appears to the user as a monochromatic surface.

SUMMARY

According to one aspect, a capacitive touch switch includes atransparent insulating panel, a filtering layer having an opaque color,a transparent icon being defined in the filtering layer, a transparentsubstrate including a capacitive electrode, the transparent substratebeing tinted to substantially match the opaque color of the filteringlayer, and a light source configured to transmit light through thetransparent substrate, the transparent icon, and the transparentinsulating panel when energized.

In some embodiments, the transparent insulating panel may comprise acolorless material. The opaque color of the filtering layer may be acolor other than black or white. The filtering layer may be disposedbetween the transparent insulating panel and the transparent substrate.In some embodiments, the transparent substrate may be a tinted plastic.The capacitive electrode may be disposed on a surface of the tintedplastic substrate. In other embodiments, the capacitive electrode may bedisposed within the tinted plastic substrate.

In some embodiments, the capacitive touch switch may further include anopaque printed circuit board positioned adjacent to the transparentsubstrate and a controller secured to the printed circuit board. Thecontroller may be electrically coupled to the capacitive electrode andto the light source. The capacitive touch switch may further include alight guide positioned to transmit light from the light source to a sideof the transparent substrate opposite the filtering layer and thetransparent insulating panel. In such embodiments, the capacitive touchswitch may further include an opaque cover positioned on a side of thelight guide opposite the transparent substrate, the opaque cover coloredto substantially match the opaque color of the filtering layer.

According to another aspect, a method of manufacturing a capacitivetouch switch includes aligning (i) an insulating panel having afiltering layer disposed thereon, the filtering layer having an opaquecolor and defining a transparent icon, and (ii) a transparent substratetinted to substantially match the opaque color of the filtering layer,the transparent substrate including a capacitive electrode. The methodfurther includes securing the transparent substrate adjacent to thefiltering layer disposed on the insulating panel.

In some embodiments, aligning the insulating panel and the transparentsubstrate may include bringing the transparent icon defined by thefiltering layer into alignment with the capacitive electrode of thetransparent substrate. In other embodiments, securing the transparentsubstrate adjacent to the filtering layer may include (i) securing thetransparent substrate to a printed circuit board and (ii) securing theprinted circuit board to the insulating panel.

In some embodiments, the method may further include positioning a lightguide adjacent to the transparent substrate and adjacent to a lightsource secured to the printed circuit board, such that light istransmitted through the transparent substrate and the transparent iconwhen the light source is energized. In other embodiments, the method mayfurther include securing an opaque cover adjacent to the light guide,the opaque cover colored to substantially match the opaque color of thefiltering layer.

According to yet another aspect, a user interface includes a transparentinsulating panel, a filtering layer disposed on the transparentinsulating panel, the filtering layer having an opaque color anddefining a plurality of transparent icons, a printed circuit boardsecured to the transparent insulating panel, the printed circuit boardhaving a void formed therein, a transparent substrate including aplurality of capacitive electrodes, the transparent substrate alignedwith the void of the printed circuit board and tinted to substantiallymatch the opaque color of the filtering layer, and a plurality oflight-emitting diodes soldered to the printed circuit board, each of thelight-emitting diodes configured to transmit light through a portion ofthe transparent substrate, one of the plurality of transparent icons,and a portion of the transparent insulating panel when energized.

In some embodiments, the opaque color of the filtering layer may be acolor other than black or white. The transparent substrate may bedisposed at least partially within the void of the printed circuitboard. In other embodiments, the user interface may further include aplurality of light guides positioned to transmit light from theplurality of light-emitting diodes to a side of the transparentsubstrate opposite the filtering layer and the transparent insulatingpanel. In such embodiments, the user interface may further include anopaque cover positioned adjacent to the plurality of light guides, theopaque cover colored to substantially match the opaque color of thefiltering layer.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is an exploded view of one embodiment of a user interface havinga dead-front effect; and

FIG. 2 is a cross-sectional view of an assembled capacitive touch switchof the user interface of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

The present disclosure relates to a user interface including one or morecapacitive touch switches capable of displaying a dead-front effect to auser. When an icon associated with one of the capacitive touch switchesis not illuminated, the user is presented with a monochromatic surface.The exploded view of FIG. 1 illustrates a pre-assembly view of thecomponents which are combined during manufacture of a user interface100. The cross-sectional, side view of FIG. 2 illustrates thesecomponents in an assembled form. Similar components are labeled usingthe same reference numerals in both figures.

As shown in FIGS. 1 and 2, an illustrative embodiment of the userinterface 100 is constructed from an insulating panel 102, a filteringlayer 104, a printed circuit board 106, a transparent substrate 108including a number of capacitive electrodes 110, a number of lightguides 112, 114, a septum 116, and an opaque cover 118, among othercomponents. The user interface 100 is illustratively shown as includingfour capacitive electrodes 110 and, thus, four capacitive touchswitches. It will be appreciated, however, that the user interface 100may include any number of capacitive touch switches in otherembodiments.

The insulating panel 102 creates a smooth front surface for the userinterface 100 and serves as a dielectric material between the user 200and the capacitive electrodes 110. The insulating panel 102 may beformed of any non-conductive material, such as plastic, glass, ceramic,or some combination thereof. The insulating panel 102 is formed of atransparent material, which allows the passage of at least some light.In some embodiments, the insulating panel 102 is formed of a “colorless”material, meaning that the panel 102 is clear and allows substantiallyall colors of light to pass through it. The insulating panel 102includes a first face 120 and an opposing, second face 122. In theembodiment shown in FIGS. 1 and 2, the insulating panel 102 isillustratively embodied as an non-tinted, non-frosted glass sheet 102,and the second face 122 is adapted to be touched by the user 200.

A filtering layer 104 may be disposed on or adjacent to the glass sheet102. The filtering layer 104 generally has an opaque color which allowsthe passage of little or no light. Select portions 124, 126 of thefiltering layer 104, however, are either missing or transparent. Theseportions 124, 126 are arranged to define a number ofappropriately-shaped, transparent icons 128 in the filtering layer 104.Thus, when the filtering layer 104 is backlit, one or more illuminatedicons 128 will be displayed to the user 200. The transparent icons 128may illustratively include multiple regions, such as lower region 124and upper region 126. Although the user interface 100 may include anynumber of transparent icons 128, one icon 128 will generally beassociated with each capacitive touch switch in the user interface 100.

The filtering layer 104 may be illustratively embodied as a thin film104 disposed on the first face 120 of the glass sheet 102. Use of thethin film 104 may improve the adaptability of the user interface 100.For example, it is possible to easily customize the user interface fordifferent countries and languages by changing only the thin film 104.Those of ordinary skill will also appreciate that the thin film 104might be disposed on the second face 122, rather than the first face120, of the glass sheet 102. Alternatively, the filtering layer 104 maybe formed as an icon serigraphy printed directly onto the first face 120or second face 122 of the glass sheet 102.

The printed circuit board (PCB) 106 carries several electroniccomponents used in the capacitive touch switch 100. The PCB 106 may beformed of an opaque material and may include wiring and electroniccomponents on one or both sides of the board. PCB 106 may be secured tothe insulating panel 102 and the filtering layer 104 using any knownmethod, such as adhesives or mechanical connections (e.g., screws), byway of example. As shown in FIG. 1, the PCB 106 may be formed to includea void 130. The void 130 is illustratively rectangular in shape. PCB 106also includes a number of terminals 132 which partially extend into thevoid 130. The terminals 132 are configured to electrically couple withcorresponding terminals 134 on the transparent substrate 108.

In the illustrative embodiment, a controller 202 and a number of lightsources 204 (both shown in FIG. 2) are soldered to the side of PCB 106opposite the insulating panel 102 and the filtering layer 104. Thecontroller 202 is electrically coupled to the capacitive electrodes 110(via terminals 132, 134) and the light sources 204. The controller 202may receive electrical signals from the capacitive electrodes 110 tosense when a user 200 has approached the capacitive touch switch 100 andmay provide electrical signals to the light sources 204 to selectivelycontrol illumination of the transparent icons 128 of the user interface100.

The light sources 204 may include any generators of visible light, suchas lamps, bulbs, vacuum fluorescents, and light-emitting diodes (LEDs),by way of example. In the presently disclosed embodiments, the lightsources 204 are illustratively embodied as a number of low-profile,side-mounted LEDs 204. The LEDs 204 may have several, distinct levels ofillumination (e.g., an “off” level, a low level, an intermediate level,a high level, etcetera), which may be used to inform a user 200 when theassociated switch 100 is inactive, active, or selected. In theillustrative embodiment, a pair of LEDs 204 are provided to illuminateeach icon 128 on the user interface 100.

The user interface 100 also includes a transparent substrate 108 whichcarries the capacitive electrodes 110. In the illustrative embodimentshown in FIG. 1, the transparent substrate 108 includes four capacitiveelectrodes 110 with corresponding terminals 134. The capacitiveelectrodes 110 may be formed of any conductive material, such as a metalor conductive polymer, which will capacitively couple with a user 200who touches the insulating panel 102. In some embodiments, such as thatshown in FIG. 2, the capacitive electrodes 110 may be disposed on asurface of the transparent substrate 108, such as by printing, forexample. In other embodiments, the capacitive electrodes 110 may bedisposed within the interior of the transparent substrate 108.Illustrative transparent substrates carrying capacitive electrodes areavailable from IGT Industries Ltd. of Eastleigh, Hampshire, UnitedKingdom.

The transparent substrate 108 which carries the capacitive electrodes110 is tinted to substantially match the opaque color of the filteringlayer 104. In the illustrative embodiment, the transparent substrate 108is comprised of a tinted plastic. The transparent nature of thesubstrate 108 allows light from an energized light source 204 to passthrough the transparent substrate 108, the transparent icon 128, and thetransparent insulating panel 102 to display an illuminated icon to theuser 200. When the light source is de-energized, however, portions ofthe substrate 108 will be visible to the user 200 through thetransparent insulating panel 102 and the transparent icon 128 offiltering layer 104. Tinting of the transparent substrate 108 tosubstantially match the opaque color of the filtering layer 104 presentsthe user 200 with the appearance of a monochromatic surface when theicon 128 is not illuminated. This monochromatic surface may be anydesired color, and the user interface 100 may achieve an effectivedead-front with colors other than black or white.

A number of light guides 112, 114 may be used to transmit light from theLEDs 204 to a side of the transparent substrate 108 opposite thefiltering layer 104 and the insulating panel 102. As shown in FIG. 2, anexterior edge of the light guide 112 receives light from a nearby LED204 and disperses this light across a portion of the transparentsubstrate 108. In the illustrative embodiment of the user interface 100shown in FIG. 1, eight light guides 112, 114 are employed (onecorresponding to each of the eight LEDs 204 discussed above). The lightguides 112, 114 may be divided by an opaque septum 116 to preventoptical interference. Four larger light guides 112 are each used totransmit light from an LED 204 to the lower region 124 of an icon 128.Similarly, four smaller light guides 114 are each used to transmit lightfrom an LED 204 to the upper region 126 of an icon 128. This arrangementallows independent illumination of the various regions 124, 126 of eachicon 128, which may be used to distinguish between functions that areavailable to a user and those that are already selected.

The user interface 100 may also include an opaque cover 118 positionedbehind the light guides 112, 114, opposite the transparent substrate108. The opaque cover 118, like septum 116, further prevents opticalinterference between the light guides 112, 114. In addition, the opaquecover 118 may be colored to substantially match the opaque color of thefiltering layer 104. Such coloring of the opaque cover 118 may furtherenhance the appearance of a monochromatic surface when a light source204 is de-energized and the corresponding icon 128 is not illuminated.The opaque cover 118 may be secured to the PCB 106 using any knownmethod, such as adhesives or mechanical connections (e.g., screws), byway of example.

When assembling the user interface 100, a manufacturer may begin with atransparent insulating panel 102. An appropriate filtering layer 104,having a desired color and the desired transparent icons 128, may bedisposed on the insulating panel 102. Next, a transparent substrate 108including a number of capacitive electrodes 110 and having theappropriate tint (which substantially matches the opaque color of thefiltering layer 104), is selected by the manufacturer. The insulatingpanel 102 is then aligned with the transparent substrate 108. In someembodiments, this may include bringing the transparent icon(s) 128defined by the filtering layer into alignment with the capacitiveelectrode(s) 110 carried by the transparent substrate 108, as shown inFIG. 1.

After alignment, the manufacturer secures the transparent substrate 108near, or possibly in contact with, the filtering layer 104 disposed onthe insulating panel 102. In some embodiments, this may be accomplishedby connecting the transparent substrate 108 to the PCB 106 and, then,securing the PCB 106 to the insulating panel 102, as described above.Once connected, the transparent substrate 108 may reside fully orpartially within the void 130 formed in the PCB 106, as shown in FIG. 2.When desirable, the manufacturer may also position light guides 112, 114near, or possibly in contact with, both the LEDs 204 and transparentsubstrate 108 and may secure the opaque cover 118 behind the lightguides 112, 114. Each of these components may be secured to one anotherusing any known method, such as adhesives or mechanical connections(e.g., screws), by way of example.

As will be appreciated by those of ordinary skill in the art, the userinterface 100 illustrated in FIGS. 1 and 2 may include elements otherthan those shown and described above, such as, by way of example,additional control and display circuitry coupled to the PCB 106. Itshould also be appreciated that the location of many components may alsobe altered. While the disclosure has been illustrated and described indetail in the drawings and foregoing description, such an illustrationand description is to be considered as exemplary and not restrictive incharacter, it being understood that only illustrative embodiments havebeen shown and described and that all changes and modifications thatcome within the spirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the apparatus, systems, and methodsdescribed herein. It will be noted that alternative embodiments of theapparatus, systems, and methods of the present disclosure may notinclude all of the features described yet still benefit from at leastsome of the advantages of such features. Those of ordinary skill in theart may readily devise their own implementations of the apparatus,systems, and methods that incorporate one or more of the features of thepresent invention and fall within the spirit and scope of the presentdisclosure as defined by the appended claims.

What is claimed is:
 1. An appliance, comprising: a body including aninterface panel; and a user interface proximate the interface panel,wherein the user interface comprises: an insulating panel; a capacitivetouch switch including a capacitive electrode; a filtering layerpositioned proximate the insulating panel and including an iconproximate the capacitive touch switch, the icon having an upper regionand a lower region, wherein the lower region encircles an indicia andthe upper region extends over the lower region and the indicia; aprinted circuit board in electrical communication with the capacitivetouch switch; a substrate positioned adjacent to the filtering layer,wherein the substrate includes an electrode terminal block incommunication with the printed circuit board; and a light sourceoperable between activated and deactivated conditions, wherein one ofthe upper region and the lower region of the icon is selectively visiblethrough the filtering layer when the light source is in the activatedcondition to define a function of the indicia and further wherein one ofthe upper and lower regions of the icon is generally selectivelyconcealed from view by the filtering layer when the light source is inthe deactivated condition.
 2. The appliance of claim 1, wherein theinsulating panel includes a smooth front surface of the user interfaceand serves as a dielectric material between a user and the capacitiveelectrode.
 3. The appliance of claim 1, wherein the capacitive electrodecomprises a conductive polymer.
 4. The appliance of claim 1, furthercomprising: a light guide positioned to transmit light from the lightsource to a side of the substrate opposite the filtering layer and theinsulating panel.
 5. The appliance of claim 4, further comprising: acover positioned adjacent to the light guide.
 6. The appliance of claim1, wherein the insulating panel includes a non-conductive material,wherein the non-conductive material is one of a plastic, glass, ceramic,or glass-ceramic material.
 7. The appliance of claim 1, furthercomprising: a controller secured to the printed circuit board.
 8. Theappliance of claim 7, wherein the controller is electrically coupled tothe capacitive electrode and to the light source.
 9. The appliance ofclaim 1, wherein the printed circuit board defines a void, the printedcircuit board including a circuit board terminal block that extendspartially into the void.
 10. A user control for an appliance,comprising: a capacitive touch switch; a filtering layer proximate aninsulating panel and including an icon that has an upper region and alower region, the lower region surrounding an indicia; a polymericmaterial proximate the filtering layer; a printed circuit boardcomprising electronic components configured to communicate with thecapacitive touch switch; and a light source operable between activatedand deactivated conditions and configured to transmit light through thepolymeric material, the light source independently transmitting lightthrough at least one of the upper region and the lower region of theicon when in the activated condition to define a functionality of theindicia.
 11. The user control of claim 10, wherein the icon isassociated with the capacitive touch switch in said user control. 12.The user control of claim 10, wherein the filtering layer includes athin film disposed on a first face of a glass sheet.
 13. The usercontrol of claim 10, wherein the icon is visible through the filteringlayer when the light source is in the activated condition, and furtherwherein the icon is generally concealed from view by the filtering layerwhen the light source is in the deactivated condition.
 14. The usercontrol of claim 10, wherein the polymeric material is a tinted plasticthat substantially matches the filtering layer.
 15. The user control ofclaim 14, further comprising: a plurality of capacitive electrodesdisposed on a surface of the tinted plastic of the polymeric material.16. The user control of claim 15, wherein the plurality of capacitiveelectrodes are disposed within the tinted plastic of the polymericmaterial.
 17. The user control of claim 15, further comprising: acontroller secured to the printed circuit board, the controllerelectrically coupled to the plurality of capacitive electrodes and tothe light source.
 18. The user control of claim 17, wherein thecontroller and the light source are coupled to a side of the printedcircuit board opposite the insulating panel and the filtering layer. 19.The user control of claim 10, further comprising: a light guidepositioned to transmit light from the light source to a side of thepolymeric material opposite the filtering layer.
 20. The user control ofclaim 10, wherein the light source independently illuminates the upperregion of the icon when in the activated condition.